The present invention relates to the manufacture of a connecting rod of the type used in internal combustion engines. The invention also relates to the elimination of vertical flash on an as-forged connecting rod.
Connecting rods are commonly manufactured using a forge die of the closed type. A closed-die forging process comprises placing a heated preform, or workpiece, between two or more punches in the forge die. The preform is compressed to plastically deform the preform into an as-forged connecting rod. The shape of the as-forged connecting rod is determined by the geometry of the punches and the amount of compressive force exerted by the forge die.
An as-forged connecting rod produced by a closed-die forging process typically includes areas of unwanted material, or flash, that project outwardly from various surfaces of the forging. Flash results from the flow of preform material into gaps that are normally present between the various components of the forge die. Flash is typically categorized as horizontal or vertical, depending on its orientation in relation to the as-forged connecting rod. Horizontal flash typically forms as a single, continuous layer of material that extends along the outer perimeter of the as-forged connecting rod. The horizontal flash is usually removed by a shearing or stamping operation using, for example, a trim die. Vertical flash, however, cannot readily be removed in this maimer. More particularly, vertical flash extends from surfaces on the as-forged connecting rod having different relative elevations. This feature necessitates the use of a relatively complicated and time-consuming sanding procedure to remove the vertical flash. The sanding procedure is typically performed on complex machinery costing $ 1,000,000 or more.
An ongoing need therefore exists for an improved process for removing vertical flash from an as-forged connecting rod. A process that requires a minimal amount of time and effort to complete is preferred. In addition, it is highly desirable that the improved process alleviate the need to use costly and complex machinery in the flash-removal process.
A presently-preferred process for manufacturing a connecting rod comprises placing a heated preform suitable for being formed into the connecting rod into a closed forge die, and forging the preform in a first forging operation while the preform is at a forging temperature to form an as-forged connecting rod having vertical flash extending therefrom. The presently-preferred process also comprises placing the as-forged connecting rod in a second forge die while the as-forged connecting rod is at a temperature substantially equal to the forging temperature, and forging the vertical flash in a second forging operation. The presently-preferred process further comprises removing the as-forged connecting rod from the second forge die, and machining the as-forged connecting rod to predetermined dimensions.
Another presently-preferred process for manufacturing a connecting rod comprises forging a preform in a first forging operation to form an as-forged connecting rod having vertical flash extending therefrom, and forging the vertical flash in a second forging operation to fold the vertical flash onto the as-forged connecting rod. The presently-preferred process also comprises machining the as-forged connecting rod to predetermined dimensions.
Another presently-preferred process for manufacturing a connecting rod comprises forging a preform in a first forging operation to form an as-forged connecting rod having vertical flash extending therefrom, and forging the vertical flash in a second forging operation to form the vertical flash into a bead. The presently-preferred process further comprises machining the as-forged connecting rod to predetermined dimensions.
Another presently-preferred process for manufacturing a connecting rod comprises forming the preform into an as-forged connecting rod having vertical flash formed thereon by forging the preform in a first forging operation, and re-forming the vertical flash by forging the vertical flash in a second forging operation.
Another presently-preferred process for manufacturing a connecting rod comprises forming a preform suitable for being formed into the connecting rod by placing powder metal in a die, compressing the power metal, and then sintering the powder metal. The presently-preferred process also comprises performing a first forging operation to form the preform into an as-forged connecting rod having vertical flash extending therefrom, and performing a second forging operation to re-form the vertical flash.
A presently-preferred process for eliminating vertical flash on an as-forged connecting rod comprises forging the vertical flash onto a surface of the as-forged connecting rod, and rounding the vertical flash to form a radius thereon.
Another presently-preferred process for eliminating vertical flash on a as-forged connecting rod comprises placing the as-forged connecting rod in a forge die, and forging the vertical flash into a bead.
A presently-preferred process for treating vertical flash extending from a surface of an as-forged connecting rod by a distance comprises placing the as-forged connecting rod in a forge die, and forging the vertical flash to reduce the distance by which the vertical flash extends from the as-forged connecting rod.